Tripoli, Libya (CNN) -- Lockerbie bomber Abdel Basset al-Megrahi is comatose, near death and likely to take secrets of the attack on Pan Am Flight 103 to his grave.

CNN found al-Megrahi under the care of his family in his palatial Tripoli villa Sunday, surviving on oxygen and an intravenous drip. The cancer-stricken former Libyan intelligence officer may be the last man alive who knows precisely who in the Libya government authorized the bombing, which killed 270 people.

"We just give him oxygen. Nobody gives us any advice," his son, Khaled al-Megrahi, told CNN.

Al-Megrahi was freed from a prison in Scotland in 2009 after serving eight years of a life sentence for blowing up the Pan Am jet, killing all 259 on board and 11 in the town of Lockerbie below. Doctors who had been treating him for prostate cancer gave him just three months to live, and he was released on compassionate grounds.

He received a hero's welcome in Tripoli, enraging many in the United States and Britain. And with the recent overthrow of longtime Libyan strongman Moammar Gadhafi, politicians on both sides of the Atlantic have called for al-Megrahi to be sent back to prison.